It is known to provide machines and systems for the preparation of beverages such as coffee, tea and chocolate. Typically, in such systems the beverage ingredients are used either in a loose form or contained in a container. It is known in some machines to use flexible containers, such as filter paper bags containing roast and ground coffee or leaf tea. It is also known in other machines to use containers in the form of cartridges which may be rigid, semi-rigid, or flexible and which are pierced during preparation of the beverage. In both cases, the machine for use with such containers is specially adapted to receive a particular design of container in a brew head and to pass water and/or steam through the container to prepare a beverage which is then dispensed. Such beverage preparation machine may be used in commercial or domestic markets. In the domestic market consumers may not wish to use separate machines when preparing beverages from different beverage ingredient containing containers or, indeed, loose beverage ingredients. It is therefore an object of the present invention to provide an insert, a beverage preparation machine and a beverage preparation system which allows consumers to use a variety of containers or loose ingredients in a single beverage preparation machine. In one aspect, it is an object of the present invention to provide an insert for a beverage preparation machine which is primarily designed for use with cartridges, whether rigid, semi-rigid or flexible, that allows the beverage preparation machine to dispense beverage ingredients from flexible containers such as filter bags.